var obj = {
  name: "frank",
  age: 18,
};
obj.__proto__ = {
  address: "北京市",
};
// console.log(obj.__proto__);
// console.log(Object.prototype);
// console.log(obj.__proto__ === Object.prototype);
// console.log(Object);
console.log(obj.__proto__.__proto__.__proto__);
console.log(Object.prototype);
